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Consideration of the possible carcinogenicity of some pesticides
Abstract:
The sophistication, sensitivity, and the predictability of carcinogenesis bioassays using small rodents is reviewed. Bioassays were conducted using both sexes of mice (B6C3F1:C57BL/6xC3H F1 hybrid) and rats (Osborne-Mendel or Fisher 344). Chemicals tested included three acaracides, two fungicides, two fumigants, four herbicides, twelve chlorinated insecticides, and five organo-phosphorus insecticides. The tumor response of each test strain and sex to the above chemicals is discussed, as well as the spontaneous tumor incidence of each strain. The results suggest caution when interpreting the data from bioassays.
Insights
This review examines rodent carcinogenesis bioassays, finding that while sophisticated, their sensitivity and predictability require cautious interpretation due to varied tumor responses and spontaneous incidence in mice and rats.
Area of Science:
- Toxicology
- Carcinogenesis
- Animal models
Background:
- Carcinogenesis bioassays are crucial for evaluating chemical safety.
- Small rodents are commonly used models in these studies.
- Understanding assay limitations is vital for accurate risk assessment.
Purpose of the Study:
- To review the sophistication, sensitivity, and predictability of rodent carcinogenesis bioassays.
- To analyze tumor responses to various chemicals across different rodent strains and sexes.
- To discuss spontaneous tumor incidence in control groups.
Main Methods:
- Review of existing literature on rodent bioassays.
- Analysis of data from studies using mice (B6C3F1) and rats (Osborne-Mendel, Fisher 344).
- Examination of tumor incidence following exposure to pesticides (acaracides, fungicides, fumigants, herbicides, insecticides).
Main Results:
- Varied tumor responses were observed in different rodent strains and sexes.
- Spontaneous tumor rates differed among the tested strains.
- The predictability of bioassays was influenced by these variations.
Conclusions:
- Rodent carcinogenesis bioassays are complex tools.
- Interpreting bioassay data requires careful consideration of strain-specific tumor responses and spontaneous incidence.
- Caution is advised when extrapolating findings from these bioassays.